Yesterday, the Government announced a crack-down on youth crime including sending the worst offenders to boot camp and fining the parents of children wandering the streets after midnight.

Speaking to TVNZ1's Breakfast, Mr English hit back at criticism that boot camps don't work for young offenders.

"We're not changing the entire system…this is dealing with the very hard end of continuously defiant and sometimes dangerous young people," Mr English said.

He says these young offenders have committed serious crimes such as murder and rape which would see them end up in adult prison.

"These are 150 of the toughest kids in New Zealand.

"For these kids the alternative to going to prison."

Mr English says the scheme would cost the same amount as sending the offenders to prison and would aim to prevent them from leading a life of crime.

When confronted with research by Breakfast presenter Jack Tame which shows the repeated failure of boot camps for young offenders overseas, Mr English continued to back up the policy saying the camps would work for very serious offenders.

"This isn't a short sharp jolt.

"This is a year with an intensive wrap round service and what we know from other intensive wrap round services is that they generally do work."

He says boot camps in the past have been aimed at would-be young offenders rather than those convicted of serious crimes.

"If we don't change what we do they just go to prison. They go in as amateur criminals and come out with a PHD in being a criminal.

"So we're trying something different. It's worth having a crack at."

Mr English says if the Government doesn't try a different method of dealing with young criminals they will continue to get the same results they are now.

If young offenders fail to complete the camps they'll be sent to prison.